[37635-87-3]  · C3H2O2S  · 2-Thiono-1,3-dioxol-4-ene  · (MW 102.12)

(dienophile in Diels-Alder reactions;1 acetylene equivalent in cycloaddition reactions;2 source of ketene;3 forms dication dichalcogenides with strong Lewis acids4)

Alternate Name: vinylene thionocarbonate.

Physical Data: mp 48 °C; bp 60-70 °C/0.2 mmHg.

Solubility: sol acetonitrile, benzene, carbon tetrachloride, dichloromethane, toluene; insol hexane.

Form Supplied in: not commercially available.

Preparative Method: prepared by reaction of Phosphorus(V) Sulfide with Vinylene Carbonate.1

Purification: recrystallization from benzene-hexane gives white crystals; sublimation at 120 °C generates long white needles.

Handling, Storage, and Precautions: material is apparently stable.

Cyclization with Dienes.

The reaction of 2-thiono-1,3-dioxol-4-ene with anthracene at elevated temperatures leads to the production of the bicyclic adduct (1) (eq 1).1,2 No other dienes have been reported to cyclize with this reagent. Diels-Alder adducts could be treated with phosphines to effect a Corey-Winter alkenation, which would render the reagent an acetylene equivalent.

Synthesis of Ketene.

Photolysis (270 nm) of 2-thiono-1,3-dioxol-4-ene results in the quantitative formation of ketene via Wolff rearrangement of the corresponding a-ketocarbenes (eq 2).3 Substituted dioxolenes can also be used in this fashion to generate substituted ketenes (eq 3). This serves as a convenient alternative to the use of a-diazo ketones in the generation of ketenes.

Preparation of Dication Dichalcogenides.

Treatment of 2-thiono-1,3-dioxol-4-ene with Trifluoromethanesulfonic Anhydride leads to the formation of the corresponding dimeric dication (eq 4).4 Hydrolysis of this stable dication with aqueous base generates equimolar amounts of both vinylene carbonate and vinylene thionocarbonate.4

1. Fischer, H.-M.; Hartmann, W. CB 1972, 105, 2769.
2. Anderson, W. K.; Dewey, R. H. JACS 1973, 95, 7161.
3. Torres, M.; Clement, A.; Strausz, O. P. JOC 1980, 45, 2271.
4. Maas, G.; Singer, B. CB 1983, 116, 3659.

James W. Leahy

University of California, Berkeley, CA, USA

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